Swimming and diving are popular sports programs. During swimming and diving, it is easily to be collided due to complex underwater environment, and the swimmer or diver has to know the underwater environment. To avoid injury, especially to avoid damage to the head, the underwater situation is needed to know in real time. However, as human eyes cannot be kept open in the water environment for a long time, the sportsman or women usually need to wear swimming goggles or diving masks during swimming and diving.